Multilayer copper bus bars with soldered through hole components

ABSTRACT

An electrical assembly, such as a multi-layer bus bar, includes an electrical connection pin and a plurality of electrically conductive layers. Each of the electrically conductive layers is formed to define a cutout therein to receive the electrical connection pin and allow access for joining material to join the electrical connection pin with the plurality of electrically conductive layers. Each of the cutouts is formed to include a first portion arranged around the electrical connection pin and a second portion located radially outward of the first portion.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to electronic components, andmore specifically to features and methods for soldering multilayerelectronic components.

BACKGROUND

In aerospace applications, power electronic converter designs may demandhigh power density in terms of weight and volume. One commonly adoptedapproach to reduce the DC link capacitance is to increase the powerconverter's switching frequency. However, with increasing switchingfrequency, the alternating current through the DC link capacitorsincrease accordingly. With increased frequency, current crowing occursin the DC link of conventional bus bars where the electrical currentonly flows to the surface of copper layers to certain depth, which istermed the skin-depth. Moreover, film capacitors may be utilized moreand more in aerospace power converters.

The combination of conventional through-hole rectangle capacitors andconventional multilayer copper bus bar or printed circuit boards createthe challenge of reliable soldering. The top most layer of conventionalcomponents may be the most assessable for soldering while the innerlayers may be difficult to reach with conventional soldering method. Thesoldering quality of conventional components may be poor where the innerlayers are barely attached to the capacitor pins.

SUMMARY

The present disclosure may comprise one or more of the followingfeatures and combinations thereof.

A multi-layer bus bar assembly according to the present disclosureincludes a capacitor and a multi-layer bus bar. The capacitor having abody and a first electrical connection pin that extends away from thebody along an axis. The multi-layer bus bar includes a positive rail, anegative rail, and a main insulation layer. The positive rail includes aplurality of first conductive layers and a plurality of firstinter-insulation layers. Each of the plurality of first inter-insulationlayers is located axially between neighboring first conductive layersincluded in the plurality of first conductive layers. The negative railincludes a plurality of second conductive layers and a plurality ofsecond inter-insulation layers. Each of the plurality of secondinter-insulation layers is located axially between neighboring secondconductive. The main insulation layer is positioned between the positiverail and the negative rail.

In illustrative embodiments, the plurality of first conductive layersare formed to assist in the joining of the plurality of first conductivelayers with the first electrical connection pin. The plurality of firstconductive layers may include a first layer and a second layer axiallyneighboring the first layer. The first layer is formed to define a firstcutout shaped with a soldering pattern arranged about the axis. Thesecond layer is formed to define a second cutout shaped with thesoldering pattern. In illustrative embodiments, the soldering patternincludes a first portion that extends circumferentially at least partwayaround the first electrical connection pin at a first radial distancerelative to the axis and a second portion that extends circumferentiallyat least partway about the first electrical connection pin at a secondradial distance relative to the axis.

In some embodiments, the second cutout formed in the second conductivelayer is offset circumferentially about the axis relative to the firstcutout formed in the first conductive layer. In some embodiments, thefirst portion fluidly opens into the second portion. In someembodiments, the second cutout is offset circumferentially from thefirst cutout by less than 90 degrees relative to the axis.

In some embodiments, the first portion of the solder pattern extendscircumferentially only partway around the axis. The first distanceprovides the first portion with a constant radius.

In some embodiments, the second portion of the solder pattern extendscircumferentially only partway around the axis. The second distanceprovides the second portion with a constant radius.

In some embodiments, the second portion of the solder pattern extendscircumferentially less than 90 degrees around the axis. In someembodiments, the second portion of the solder pattern extendscircumferentially at least 90 degrees around the axis.

In some embodiments, the solder pattern further includes a third portionthat extends circumferentially at least partway about the firstelectrical connection pin at a third radial distance relative to theaxis. The third radial distance is greater than the first radialdistance.

According to another aspect, a multi-layer electrical component assemblyincludes an electrical connection pin that extends along an axis, afirst conductive layer, and a second conductive layer. The firstconductive layer is formed to define a first cutout that extends axiallythrough the first conductive layer. The first cutout includes a firstportion arranged around the electrical connection pin and a secondportion located radially outward of the first portion. The secondconductive layer axially neighbors the first conductive layer. Thesecond conductive layer is formed to define a second cutout that extendsaxially through the second conductive layer. The second cutout includesa third portion arranged around the electrical connection pin and afourth portion located radially outward of the third portion. The fourthportion is at least partially circumferentially aligned with the secondportion of the first cutout to allow joining material to be providedaxially between the fourth portion and the second portion.

In some embodiments, the second cutout is substantially the same as thefirst cutout. The second cutout is offset circumferentially relative tothe first cutout about the axis.

In some embodiments, the first portion extends circumferentially partwayabout the axis at a first constant radius. The second portion extendscircumferentially partway about the axis at a second constant radiusthat is different than the first constant radius.

In some embodiments, the second portion opens fluidly into first portionto form a single opening through the first conductive layer. In someembodiments, the second portion is entirely spaced apart radially fromthe first portion so that each of the first portion and the secondportion form an opening that extends axially through the firstconductive layer.

In some embodiments, the first cutout is defined in part by a first sidewall and a second side wall that diverge as they extend radially awayfrom the axis.

In some embodiments, the first conductive layer includes a plurality ofside walls that extend axially entirely through the first conductivelayer and define the first cutout. The plurality of first side wallsinclude a first side wall that extends circumferentially at leastpartway about the axis, a second side wall that extendscircumferentially at least partway about the axis, and a third side wallthat extends radially between and interconnects the first side wall andthe second side wall.

According to another aspect, a method of making a multi-layer bus barassembly includes a number of steps. The method includes arranging afirst cutout formed in a first electrically conductive layer around anelectrical connection pin that extends along an axis, the first cutouthaving a first portion that extends circumferentially at least partwayaround the electrical connection pin relative to the axis and a secondportion located radially outward from the first portion, arranging asecond cutout formed in a second electrically conductive layer aroundthe electrical connection pin, the second cutout having a third portionthat extends circumferentially at least partway around the electricalconnection pin relative to the axis and a fourth portion locatedradially outward from the second portion, applying joining material inthe first portion of the first cutout to cause the joining material toengage the first electrically conductive layer and the electricalconnection pin, and applying the joining material in the second portionof the first cutout to cause a portion of the joining material to passthrough the second portion of the first cutout and enter the fourthportion of the second cutout to allow the joining material to engage thesecond electrically conductive layer.

In some embodiments, the third portion of the second cutout is radiallyopen to and fluidly connected with the fourth portion to allow thejoining material into the fourth portion and into the third portion. Insome embodiments, the second portion of the first cutout has an areathat is larger than an area of the first portion. In some embodiments,the second cutout is substantially the same shape as the first cutoutand rotated circumferentially partway about the axis relative to firstcutout.

These and other features of the present disclosure will become moreapparent from the following description of the illustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a multi-layer electricalcomponent assembly, the illustrative assembly being a multi-layer busbar assembly having a capacitor and a plurality of conductive layersconfigured to be soldered with the capacitor;

FIG. 2 is top view of the multi-layer bus bar assembly of FIG. 1 showingthe capacitor soldered with the plurality of conductive layers;

FIG. 3 is a perspective view of an electrical connection pin of thecapacitor extending through cutouts formed in the plurality ofconductive layers of the multi-layer bus bar assembly and suggestingthat the cutouts have a similar solder pattern that is offset for eachlayer to provide additional surface area and improve the solder joint;

FIG. 4 is an exploded view of the plurality of conductive layers of themulti-layer bus bar assembly showing that each layer is formed to definea cutout with the solder pattern whereby the solder pattern is offsetcircumferentially relative to an axis for each layer;

FIG. 5 is an elevation view of another solder pattern for use with theconductive layers of the multi-layer electrical component;

FIG. 6 is an elevation view of another solder pattern for use with theconductive layers of the multi-layer electrical component;

FIG. 7 is an exploded view of a plurality of conductive layers ofanother embodiment of the solder pattern for use with the multi-layerelectrical component assembly showing that each layer is formed todefine a cutout with the solder pattern whereby all solder patterns arealigned circumferentially relative to an axis for each layer; and

FIG. 8 is an exploded view of a plurality of conductive layers ofanother embodiment of the solder pattern for use with the multi-layerelectrical component assembly showing that each layer is formed todefine a cutout with the solder pattern whereby all solder patterns arealigned circumferentially relative to an axis for each layer.

DETAILED DESCRIPTION OF THE DRAWINGS

For the purposes of promoting an understanding of the principles of thedisclosure, reference will now be made to a number of illustrativeembodiments illustrated in the drawings and specific language will beused to describe the same.

A multi-layer electrical component assembly 10 for use with gas turbineengines is shown in FIG. 1 . The multi-layer electrical componentassembly 10 may be, for example, a multi-layer bus bar or printedcircuit board (PCB). The multi-layer electrical component assembly 10includes a plurality of conductive layers 28 having cutouts 32, 34, 36,etc. formed therein to assist in the joining or soldering of theconductive layers 28 with another electrical component such as aconnection pin 18A.

Each of the cutouts 32, 34, 36, etc. is shaped as a soldering pattern 26as shown in FIG. 4 . The soldering pattern 26 includes a first portion40 arranged around the connection pin 18A or other electrical componentand a second portion 42 located outward of the first portion 40 andconfigured to allow the solder or other bonding material 31 to beprovided between the conductive layers 28.

The illustrative multi-layer electrical component assembly 10 is amulti-layer bus bar assembly as shown in FIG. 1 . However, the featuresof the present disclosure are applicable to other multi-layer electricalcomponent assemblies such as, for example, printed circuit boards. Themulti-layer electrical component assembly 10 includes a capacitor 12 anda multi-layer bus bar 14 (sometimes called a laminated bus bar) coupledwith the capacitor 12 as shown in FIG. 2 .

The capacitor 12 is illustratively a film capacitor. The capacitor 12includes a body 16 having the capacitor internals therein and one ormore electrical connection pins 18A, 18B, etc. that extend away from thecapacitor body 16. Each electrical connection pin 18A, 18B, etc. extendsaway along a respective axis 15.

The multi-layer bus bar 14 includes a positive rail 22, a negative rail24, and a main insulation layer 25 as shown in FIG. 1 . The positiverail 22 is joined with at least one of the electrical connection pins18A of the capacitor 12. The negative rail 24 is joined with at leastone other of the electrical connection pins 18B of the capacitor 12. Themain insulation layer 25 is non-conductive and located between thepositive rail 22 and the negative rail 24.

The positive rail 22 includes a plurality of first conductive layers 28and a plurality of first inter-insulation layers 30 engaged with thefirst conductive layers 28 as shown in FIG. 1 . The plurality of firstconductive layers 28 is made of a conductive material such as copper,for example. At least one layer of the plurality of firstinter-insulation layers 30 is located axially between neighboring firstconductive layers 28 to provide a non-conductive insulation between theneighboring first conductive layers 28. Illustratively, the plurality offirst inter-insulation layers 30 are directly engaged with the firstconductive layers 28.

As an example, the plurality of first conductive layers 28 includes afirst conductive layer 28A, a second conductive layer 28B, and a thirdconductive layer 28C as shown in FIG. 1 . The plurality of firstinter-layer insulation layers 30 include a first insulation layer 30A, asecond insulation layer 30B, and a third insulation layer 30C. The firstinsulation layer 30A is between the first conductive layer 28A and themain insulation layer 25. The second insulation layer 30B is locatedaxially between neighboring conductive layers 28A, 28B. The thirdinsulation layer 30C is located axially between the second conductivelayer 28B and the third conductive layer 28C. The main insulation layer25 is engaged with the conductive layer 28A. In other embodiments, theplurality of first conductive layers 28 include any number of layers andthe plurality of first inter-insulation layers 30 include a number oflayers correlated with the conductive layers 28.

The plurality of first conductive layers 28 are formed to assist in thejoining of the plurality of first conductive layers 28 with the firstelectrical connection pin 18A. The first conductive layer 28A is formedto define a first cutout 32 shaped with a soldering pattern 26 arrangedabout the axis 15 as shown in FIG. 4 . The second conductive layer 28Bis formed to define a second cutout 34 shaped with the same solderingpattern 26. The third conductive layer 28C is formed to define a thirdcutout 36 shaped with the same soldering pattern 26.

In the illustrative embodiment, the cutouts 32, 34, 36 are offset ormisaligned circumferentially about the axis 15 relative to one anotheras shown in FIGS. 3 and 4 . In other words, the shape of solderingpattern 26 is the same for each conductive layer 28A, 28B, 28C, butrotated partially around the axis 15 relative to the neighboringconductive layer 28A, 28B, 28C. In other embodiments, the cutouts 32,34, 36 are substantially aligned circumferentially about the axis 15relative to one another.

The soldering pattern 26 includes a first portion 40, a second portion42, and a third portion 44 as shown in FIG. 4 . The first portion 40 isaligned on the axis 15 and is sized to receive the electrical connectionpin 18A. The first portion 40 extends circumferentially at least partwayaround the first electrical connection pin 18A at a first radialdistance relative to the axis 15. The second portion 42 is locatedradially outward of the first portion 40 and extends at least partwayabout the first electrical connection pin 18A at a second radialdistance relative to the axis 15. In the illustrative embodiment, thesecond portion 42 is wedge shaped. In the illustrative embodiment, thesecond portion 42 opens into the first portion 40 so that the firstportion 40 and the second portion 42 are in fluid communication with oneanother to form a single opening. The third portion 44 is locatedradially outward of the first portion 40 opposite the second portion 42and extends at least partway about the first electrical connection pin18A at a third radial distance relative to the axis 15. The third radialdistance is equal to the second radial distance in this embodiment. Inthe illustrative embodiment, the third portion 44 is wedge shaped. Inthe illustrative embodiment, the third portion 44 opens into the firstportion 40 so that the first portion 40 and the third portion 44 are influid communication with one another.

In the illustrative embodiment, the second portion 42 extends less than180 degrees around the axis 15. In some embodiments, the second portion42 extends more than 180 degrees around the axis 15 and less than 360degrees around the axis 15. In some embodiments, the second portion 42extends less than 90 degrees around the axis 15. In some embodiments,the second portion 42 extends less than 45 degrees around the axis 15.In some embodiments, the second portion 42 extends less than 30 degreesaround the axis 15. In other embodiments, the second portion 42 extendsat least 90 degrees around the axis 15.

The cutout 32 includes a first inner wall 46, a second inner wall 48, afirst outer wall 50, a second outer wall 52, a first intermediate wall54, a second intermediate wall 56, a third intermediate wall 58, and afourth intermediate wall 60 as shown in FIG. 4 . The first inner wall 46and the second inner wall 48 are curved and each extend partwaycircumferentially around the axis 15 at the first radius as shown inFIG. 4 . The first inner wall 46 and the second inner wall 48 cooperateto define the first portion 40 of the soldering pattern 26. The firstinner wall 46 and the second inner wall 48 are configured to be bondeddirectly with the electrical connection pin 18A with solder or otherjoining material 31.

The first outer wall 50 and the second outer wall 52 extendcircumferentially partway around the axis 15 at the second radius asshown in FIG. 4 . The first outer wall 50 and the second outer wall 52are each curved walls and each extend less than 180 degrees around theaxis 15.

The first intermediate wall 54 extends between and interconnects thefirst inner wall 46 and the first outer wall 50 as shown in FIG. 4 . Thesecond intermediate wall 56 extends between and interconnects the secondinner wall 48 and the first outer wall 50. The first intermediate wall54 and the second intermediate wall 56 diverge away from each other asthey extend radially outward away from the axis 15.

The third intermediate wall 58 extends between and interconnects thefirst inner wall 46 and the second outer wall 52 as shown in FIG. 4 .The fourth intermediate wall 60 extends between and interconnects thesecond inner wall 48 and the second outer wall 52. The thirdintermediate wall 58 and the fourth intermediate wall 60 diverge awayfrom each other as they extend radially outward away from the axis 15.

As shown in FIG. 4 , the solder pattern 26 is the same for each cutout32, 34, 36 of the conductive layers 28A, 28B, 28C respectively. The samesolder patterns 26 is rotated circumferentially about the axis 15 foreach conductive layers 28A, 28B, 28C so that they are not alignedcircumferentially. As shown in FIG. 3 , the circumferential offsetprovides a stepped feature. Each of the first portions 40 of theconductive layers 28A, 28B, 28C are similarly sized and receive theelectrical connection pin 18A. The second and third portions 42, 44 ofthe conductive layers 28A, 28B, 28C form the stepped features. As aresult, a portion of each conductive layers 28A, 28B is exposed for thesolder or joining material 31 to couple the conductive layers 28A, 28B,28C with the electrical connection pin 18A. The second portions 42 areopen to each other and open to the first portions 40 to allow the solderor joining material 31 to flow into the other second portions 42 andfirst portions 40 from one more second portions 42.

Another embodiment of a cutout 232 for conductive layers and having asolder pattern 226 is shown in FIG. 5 . The cutout 232 is formed in aconductive layer 228A included in a plurality of conductive layers (notshown) for a multi-layer bus bar 214. Similar to the conductive layers28, the conductive layers 228 each include a cutout having the samesolder pattern 226, but with the pattern rotated partway around the axis215 for each layer 228 so that the patterns are misaligned when viewedradially.

The soldering pattern 226 includes a first portion 240, a second portion242, and a third portion 244 as shown in FIG. 5 . The first portion 240is aligned on the axis 215 and is sized to receive the electricalconnection pin 18A. The second portion 242 is located radially outwardof the first portion 240 and extends at least partway about the firstelectrical connection pin 18A at a second radial distance relative tothe axis 215. The third portion 244 is located radially outward of thefirst portion 240 opposite the second portion 242 and extends at leastpartway about the first electrical connection pin 18A at a third radialdistance relative to the axis 215.

In the illustrative embodiment, the second portion 242 extends about orless than 90 degrees around the axis 215. In some embodiments, thesecond portion 242 extends about or less than 70 degrees around the axis215. In some embodiments, the second portion 242 extends about or lessthan 60 degrees around the axis 215. In some embodiments, the secondportion 242 extends about or less than 50 degrees around the axis 215.In some embodiments, the second portion 242 extends about or less than45 degrees around the axis 215. In some embodiments, the second portion242 extends about or less than 30 degrees around the axis 215.

Similar to the cutout 32, the cutout 232 includes a first inner wall246, a second inner wall 248, a first outer wall 250, a second outerwall 252, a first intermediate wall 254, a second intermediate wall 256,a third intermediate wall 258, and a fourth intermediate wall 260 asshown in FIG. 5 . The first inner wall 246 and the second inner wall 248are curved and each extend partway circumferentially around the axis 215at the first radius. The first inner wall 246 and the second inner wall248 cooperate to define the first portion 240 of the soldering pattern226. The first inner wall 246 and the second inner wall 248 areconfigured to be bonded directly with the electrical connection pin 18Awith solder or other joining material 31.

Another embodiment of a cutout 332 for conductive layers and having asolder pattern 326 is shown in FIG. 6 . The cutout 332 is formed in aconductive layer 328A included in a plurality of conductive layers (notshown) for a multi-layer bus bar 314. Similar to the conductive layers28, the conductive layers 328 each include a cutout having the samesolder pattern 326, but with the pattern rotated partway around the axis315 for each layer 328 so that the patterns are misaligned when viewedradially.

The soldering pattern 326 includes a first portion 340 and a secondportion 342 as shown in FIG. 6 . The soldering pattern 326 does notinclude a third portion. The first portion 340 is aligned on the axis315 and is sized to receive the electrical connection pin 18A. Thesecond portion 342 is located radially outward of the first portion 340and extends at least partway about the first electrical connection pin18A at a second radial distance relative to the axis 315.

In the illustrative embodiment, the second portion 342 extends about ormore than 180 degrees around the axis 315. In other embodiments, thesecond portion 342 extends about or less than 180 degrees around theaxis 315. In other embodiments, the second portion 342 extends about orless than 90 degrees around the axis 315. In other embodiments, thesecond portion 342 extends at least 90 degrees around the axis 315. Inother embodiments, the second portion 342 extends about or less than 70degrees around the axis 315. In some embodiments, the second portion 342extends about or less than 60 degrees around the axis 315. In someembodiments, the second portion 342 extends about or less than 50degrees around the axis 315. In some embodiments, the second portion 342extends about or less than 45 degrees around the axis 315. In someembodiments, the second portion 342 extends about or less than 30degrees around the axis 315.

The cutout 332 includes a first inner wall 346, a first outer wall 350,a first intermediate wall 354, and a second intermediate wall 356 asshown in FIG. 6 . The first inner wall 346 is curved and extends partwaycircumferentially around the axis 315 at the first radius. The firstinner wall 346 defines the first portion 340 of the soldering pattern326. The first inner wall 346 is configured to be bonded directly withthe electrical connection pin 18A with solder or other joining material31. The first intermediate wall 354 extends between and interconnectsthe first inner wall 346 and the first outer wall 350. The secondintermediate wall 356 extends between and interconnects the first innerwall 346 and the first outer wall 350. The first intermediate wall 354and the second intermediate wall 356 diverge as they extend radiallyoutward. The first intermediate wall 354 and the second intermediatewall 356 are generally linear.

Another embodiment of a multi-layer bus bar 414 for use with themulti-layer electrical component assembly 10 is shown in FIG. 7 . Themulti-layer bus bar 414 is substantially the same as the multi-layer busbar 14 except where the description and drawings diverge from themulti-layer bus bar 14. The multi-layer bus bar 414 includes a pluralityof conductive layers 428A, 428B, 428C, etc.

Each conductive layer 428A, 428B, 428C, etc. is formed to define acutout 432, 434, 436 having a solder pattern 426 as shown in FIG. 7 .Unlike the patterns 26, 226, 326, the solder patterns 426 are notrotated relative to each about the axis 415. In other embodiments, thepatterns 426 on different layers are offset circumferentially. Thesolder patterns 426 on each conductive layer 428A, 428B, 428C, etc. arealigned circumferentially with one another. In other embodiments, thesoldering patterns 426 may be partially misaligned with one another.

The soldering pattern 426 includes a first portion 440 and a pluralityof second portions 442 as shown in FIG. 7 . Illustratively, the firstportion 440 is a central through hole 440 and the plurality of secondportions 442 are a plurality of secondary holes or slots 442 arrangedcircumferentially around the axis 415. The first portion 440 is alignedon the axis 415 and is sized to receive the electrical connection pin18A. The second portions 442 are located radially outward of the firstportion 440 a second radial distance relative to the axis 415.

The second portions 442 are discrete relative to each other and relativeto the first portion 440 as shown in FIG. 7 . In other words, the secondportions 442 do not open directly to each other and do not open directlyinto the first portion 440. illustratively, each second portion 442 isan elongated slot that extends along a major axis that extends radiallyaway from the axis 415. The plurality of second portions 442 includeeight second portions 442 in the illustrative embodiment. In otherembodiments, the plurality of second portions 442 include any number ofsecond portions 442.

Each second portion 442 has an inner end that is located about two timesthe radius of the first portion 440. Each second portion 442 isapproximately rectangular shaped with curved edges. The second portions442 are generally equally spaced apart from one anothercircumferentially about the axis 415.

Another embodiment of a multi-layer bus bar 514 for use with themulti-layer electrical component assembly 10 is shown in FIG. 8 . Themulti-layer bus bar 514 is substantially the same as the multi-layer busbar 14 except where the description and drawings diverge from themulti-layer bus bar 14. The multi-layer bus bar 514 includes a pluralityof conductive layers 528A, 528B, 528C, etc.

Each conductive layer 528A, 528B, 528C, etc. is formed to define acutout 532, 534, 536 having a solder pattern 526 as shown in FIG. 8 .The solder patterns 526 are not rotated relative to each about the axis515. In other embodiments, the patterns 526 on different layers areoffset circumferentially. The solder patterns 526 on each conductivelayer 528A, 528B, 528C, etc. are aligned circumferentially with oneanother. In other embodiments, the soldering patterns 526 may bepartially misaligned with one another.

The soldering pattern 526 includes a first portion 540 and a pluralityof second portions 542 as shown in FIG. 8 . Illustratively, the firstportion 540 is a central through hole 540 and the plurality of secondportions 542 are a plurality of secondary holes or slots 542 arrangedcircumferentially around the axis 515. The first portion 540 is alignedon the axis 515 and is sized to receive the electrical connection pin18A. The second portions 542 are located radially outward of the firstportion 540 a second radial distance relative to the axis 515.

The second portions 542 are discrete relative to each other and relativeto the first portion 540 as shown in FIG. 8 . In other words, the secondportions 542 do not open directly to each other and do not open directlyinto the first portion 540. illustratively, each second portion 542 iswedge shaped and generally triangular. The plurality of second portions542 include eight second portions 542 in the illustrative embodiment. Inother embodiments, the plurality of second portions 542 include anynumber of second portions 542.

Each second portion 542 has an inner end that is located about two timesthe radius of the first portion 540. Each second portion 542 isapproximately triangular shaped with curved edges. The second portions542 are generally equally spaced apart from one anothercircumferentially about the axis 515. The second portions 542 are eachsubstantially similar in shape and size.

A method of making a multi-layer electrical component assembly 10 suchas a multi-layer bus bar assembly include arranging a first cutout 32formed in a first electrically conductive layer 28A around an electricalconnection pin 18A that extends along an axis 15. The first cutout 32has a first portion 40 that extends circumferentially at least partwayaround the electrical connection pin 18A relative to the axis 15 and asecond portion 42 located radially outward from the first portion 40. Asecond cutout 34 formed in a second electrically conductive layer 28B isarranged around the electrical connection pin 18A.

The second cutout 34 has a portion 40 that extends circumferentially atleast partway around the electrical connection pin 18A relative to theaxis 15 and a portion 42 located radially outward from the portion 40.Joining material 31 is applied in the first portion 40 of the firstcutout 32 to cause the joining material 31 to engage the firstelectrically conductive layer 28A and the electrical connection pin 18A.The joining material 31 is applied to the second portion 42 of the firstcutout 32 to cause a portion of the joining material 31 to pass throughthe second portion 42 of the first cutout 32 and enter the portion 42 ofthe second cutout 34 to allow the joining material 31 to engage thesecond electrically conductive layer 28B.

The portion 40 of the second cutout 34 is radially open to and fluidlyconnected with the portion 42 to allow the joining material 31 to beapplied to the portion 40. The second portion 42 of the first cutout 32has an area that is larger than an area of the first portion 40. Thesecond cutout 34 is substantially the same shape as the first cutout 32and rotated circumferentially partway about the axis 15 relative tofirst cutout 32. In some embodiments, the second cutout 434, 534 issubstantially the same shape as the first cutout 432, 532 and alignedcircumferentially relative to the axis 15 with the first cutout 432,532.

The present application provides soldering through hole components toelectronic components such as multi-layer laminated bus bars 14. Inaerospace applications, power electronic converter designs may demandhigh power density in terms of weight and volume. One commonly adoptedapproach to reduce the DC link capacitance is to increase the powerconverter's switching frequency. However, with increasing switchingfrequency, the alternating current through the DC link capacitorsincrease accordingly.

With increased frequency, current crowing occurs in the DC link ofconventional bus bars where the electrical current only flows to thesurface of copper layers to certain depth, which is termed theskin-depth. As one illustrative example, to obtain 1 millimetereffective copper thickness, a conventional bus bar can theoretically besimply a single layer of 1 millimeter copper. However, at high frequencyabove 50 kHz, multiple insulated thinner layers connected in parallelwould be used to obtain the 1 millimeter effective copper thickness. Themultilayer laminated bus bar concept is shown in FIG. 1 . The featuresof the present disclosure can be realized with either laminated bus bartechniques or with printed circuit boards. The multi-layer bus bar 14may represent one of the future trend for aerospace power converterswith higher and higher switching frequencies.

Film capacitors 12 in the form of rectangle packages with through-holepins 18, as shown in FIGS. 1 and 2 , may have the widest convergence ofspecifications including voltage ratings, unit capacitance, and unitroot mean square (rms) current. Film capacitors may also have high powerdensities. For DC link applications, unique combinations of capacitanceand root mean square current may be able to be realized withoff-the-shelf models, thus allowing fast production cycle and costsaving. Film capacitors may be utilized more and more in aerospace powerconverters.

The combination of conventional through-hole rectangle capacitors andconventional multilayer copper bus bar or printed circuit boards createthe challenge of reliable soldering. The top most layer of conventionalcomponents may be the most assessable for soldering while the innerlayers may be difficult to reach with conventional soldering method. Thesoldering quality of conventional components may be poor where the innerlayers are barely attached to the capacitor pins. Poor soldering maycreate high contact resistance which may lead to overheating of thecontact area, melting of the insulation, and short circuit in the DClink. For multilayer printed circuit boards with thick copper, theexisting conventional method to ease soldering is to pre-heat theprinted circuit board and capacitors. However, soldering quality and/orsolder penetration into the full thickness of the printed circuit boardmay be less than desirable.

According to the present disclosure, a unique layer by layer pattern 26is provided on the copper layers 28 to create easy-to-access features asshown in FIGS. 3 and 4 . Each copper layer 28 carries a thermal relivingsolder pattern 26. From one copper layer 28 to the next copper layer 28,the pattern 26 is skewed by a certain degrees in some embodiments. Whenstacked up, the coper layers 28 together create a staircase patternaround the capacitor pin 18A. As a result, each copper layer 28 can bewelded or soldered to the capacitor pin 18A separately and the bondingquality may be improved. Other thermal relieving patterns 226, 326 forcopper layers are shown in FIGS. 5 and 6 .

In other embodiments, the soldering patterns 426, 526 include a centralthrough hole 440, 540 and a plurality of secondary holes or slots 442,542 as shown in FIGS. 7-9 . In the embodiment with soldering pattern426, the pad is split into two sections to create the continuous coppercondition area from the capacitor pin 18A. In the soldering pattern 526,a single section of the copper is kept for the current condition.Besides soldering irons, resistance welders or spot welders can be usedto the capacitor pin soldering.

While the disclosure has been illustrated and described in detail in theforegoing drawings and description, the same is to be considered asexemplary and not restrictive in character, it being understood thatonly illustrative embodiments thereof have been shown and described andthat all changes and modifications that come within the spirit of thedisclosure are desired to be protected.

What is claimed is:
 1. A multi-layer bus bar assembly comprising, acapacitor having a body and a first electrical connection pin thatextends away from the body along an axis, a multi-layer bus bar thatincludes a positive rail that includes a plurality of first conductivelayers and a plurality of first inter-insulation layers, wherein each ofthe plurality of first inter-insulation layers is located axiallybetween neighboring first conductive layers included in the plurality offirst conductive layers, a negative rail that includes a plurality ofsecond conductive layers and a plurality of second inter-insulationlayers, wherein each of the plurality of second inter-insulation layersis located axially between neighboring second conductive, and a maininsulation layer positioned between the positive rail and the negativerail, wherein the plurality of first conductive layers are formed toassist in the joining of the plurality of first conductive layers withthe first electrical connection pin, the plurality of first conductivelayers include a first layer and a second layer axially neighboring thefirst layer, the first layer formed to define a first cutout shaped witha soldering pattern arranged about the axis, and the second layer formedto define a second cutout shaped with the soldering pattern, and whereinthe soldering pattern includes a first portion that extendscircumferentially at least partway around the first electricalconnection pin at a first radial distance relative to the axis and asecond portion that extends circumferentially at least partway about thefirst electrical connection pin at a second radial distance relative tothe axis.
 2. The multi-layer bus bar assembly of claim 1, wherein thesecond cutout formed in the second conductive layer is offsetcircumferentially about the axis relative to the first cutout formed inthe first conductive layer.
 3. The multi-layer bus bar assembly of claim2, wherein the second cutout is offset circumferentially from the firstcutout by less than 90 degrees relative to the axis.
 4. The multi-layerbus bar assembly of claim 1, wherein the first portion of the solderpattern extends circumferentially only partway around the axis and thefirst distance provides the first portion with a constant radius.
 5. Themulti-layer bus bar assembly of claim 4, wherein the second portion ofthe solder pattern extends circumferentially only partway around theaxis and the second distance provides the second portion with a constantradius.
 6. The multi-layer bus bar assembly of claim 5, wherein thesecond portion of the solder pattern extends circumferentially less than90 degrees around the axis.
 7. The multi-layer bus bar assembly of claim5, wherein the second portion of the solder pattern extendscircumferentially at least 90 degrees around the axis.
 8. Themulti-layer bus bar assembly of claim 1, wherein the solder patternfurther includes a third portion that extends circumferentially at leastpartway about the first electrical connection pin at a third radialdistance relative to the axis and the third radial distance is greaterthan the first radial distance.
 9. The multi-layer bus bar assembly ofclaim 1, wherein the first portion fluidly opens into the secondportion.
 10. A multi-layer electrical component assembly comprising anelectrical connection pin that extends along an axis, a first conductivelayer formed to define a first cutout that extends axially through thefirst conductive layer, and the first cutout includes a first portionarranged around the electrical connection pin and a second portionlocated radially outward of the first portion, a second conductive layerthat axially neighbors the first conductive layer, the second conductivelayer formed to define a second cutout that extends axially through thesecond conductive layer, the second cutout includes a third portionarranged around the electrical connection pin and a fourth portionlocated radially outward of the third portion, and the fourth portion isat least partially circumferentially aligned with the second portion ofthe first cutout to allow joining material to be provided axiallybetween the fourth portion and the second portion.
 11. The multi-layerelectrical component assembly of claim 10, wherein the second cutout issubstantially the same as the first cutout and offset circumferentiallyrelative to the first cutout about the axis.
 12. The multi-layerelectrical component assembly of claim 10, wherein the first portionextends circumferentially partway about the axis at a first constantradius and the second portion extends circumferentially partway aboutthe axis at a second constant radius that is different than the firstconstant radius.
 13. The multi-layer electrical component assembly ofclaim 10, wherein the second portion opens fluidly into first portion toform a single opening through the first conductive layer.
 14. Themulti-layer electrical component assembly of claim 10, wherein thesecond portion is entirely spaced apart radially from the first portionso that each of the first portion and the second portion form an openingthat extends axially through the first conductive layer.
 15. Themulti-layer component electrical assembly of claim 10, wherein the firstcutout is defined in part by a first side wall and a second side wallthat diverge as they extend radially away from the axis.
 16. Themulti-layer electrical component assembly of claim 10, wherein the firstconductive layer includes a plurality of side walls that extend axiallyentirely through the first conductive layer and define the first cutout,the plurality of first side walls include a first side wall that extendscircumferentially at least partway about the axis, a second side wallthat extends circumferentially at least partway about the axis, and athird side wall that extends radially between and interconnects thefirst side wall and the second side wall.
 17. A method of making amulti-layer bus bar assembly, the method comprising arranging a firstcutout formed in a first electrically conductive layer around anelectrical connection pin that extends along an axis, the first cutouthaving a first portion that extends circumferentially at least partwayaround the electrical connection pin relative to the axis and a secondportion located radially outward from the first portion, arranging asecond cutout formed in a second electrically conductive layer aroundthe electrical connection pin, the second cutout having a third portionthat extends circumferentially at least partway around the electricalconnection pin relative to the axis and a fourth portion locatedradially outward from the second portion, applying joining material inthe first portion of the first cutout to cause the joining material toengage the first electrically conductive layer and the electricalconnection pin, and applying the joining material in the second portionof the first cutout to cause a portion of the joining material to passthrough the second portion of the first cutout and enter the fourthportion of the second cutout to allow the joining material to engage thesecond electrically conductive layer.
 18. The method of claim 17,wherein the third portion of the second cutout is radially open to andfluidly connected with the fourth portion to allow the joining materialinto the fourth portion and into the third portion.
 19. The method ofclaim 17, wherein the second portion of the first cutout has an areathat is larger than an area of the first portion.
 20. The method ofclaim 17, wherein the second cutout is substantially the same shape asthe first cutout and rotated circumferentially partway about the axisrelative to first cutout.